A common feature provided by service providers of virtual local area networks (VLANs) is virtual private LAN service (VPLS). VPLS provides private connections through the service provider's network connecting two or more customer sites. From the customer's perspective, the two or more sites of a VLAN appear to be on the same local LAN, despite the fact that the two or more sites may be on separate networks in different geographic areas. In providing the customer with a VLAN, the service provider may configure the provider's edge routers to which the customer's two or more networks are connected to be members of the same group (the group associated with the customer). Each of the edge routers in the group may further be configured with the services that are to be supported by the group.
One way in which traffic is routed within a VLAN or a VPLS VLAN is through the use of multi-protocol label switching (MPLS). In MPLS frames or packets are assigned labels which are used to make forwarding decisions. Prior to receiving a packet, a node will have told all of its neighbors which labels to use for which services. Each service at each neighbor is assigned a different value. These values are negotiated with an exchange of signaling between the node and its neighbors. Based on the negotiated value of a single label the node is able to determine where the packet is to be forwarded.